The seasonal progress of (a) absolute peat temperatures at 2 m below the hollow surface throughout the DPH treatment period and (b) the temperature depth profiles associated with the 16 June 2015 coring event. This coring event took place 10 months after the deep peat temperature differentials were stable. In a, blue denotes control (+0 °C) plots, green denotes +2.25 °C plots, gold denotes +4.5 °C plots, orange denotes +6.75 °C plots, and red denotes +9 °C plots. In b, circles denote control (+0 °C) plots, squares denote +2.25 °C plots, diamonds denote +4.5 °C plots, triangles denote +6.75 °C plots and inverted triangles denote +9 °C plots. In the absence of air warming during this phase of the experiment, anticipated energy loss reduced the separation among treatment temperatures at the surface.